JPWO2020095453A1 - Laminated modeling equipment - Google Patents

Abstract

The laminated molding apparatus according to the present invention performs additional processing by laminating the molten processing material (7) at the processing position while moving the processing position on the work (3), and repeats the additional processing to form a modeled object (a modeled object (7). A laminated modeling device that forms 4), the processing optical system (20) that forms an image of the processing light that melts the processing material (7) at the processing position, and the measurement position that is different from the processing position on the work (3). On the light receiving optical system (30) and the light receiving unit (17), which includes a line illumination (8) that irradiates the illumination light for measurement, and a light receiving unit (17) that receives the reflected light reflected at the measurement position. The light receiving optical system (30) reflects at the measurement position, and includes a calculation unit that calculates the height of the modeled object (4) formed on the work (3) based on the light receiving position of the reflected light in. A light-shielding mask (15) is provided at the imaging position of the reflected light incident on the light receiving portion (17) to transmit the light, and to block the light at the imaging position of the light incident from the processing position.

Description

The present invention relates to a laminated modeling apparatus that forms a modeled object by melting and laminating a processed material at a processing position.

In a laminated molding technique for laminating processing materials to form a three-dimensional modeled object such as a 3D printer, there is a directed energy deposition (DED) method as a method for laminating a metal as a processing material. The DED metal laminating device supplies a metal material such as a metal wire or metal powder to a base plate as a processing material from a supply port, and melts and laminates the metal material with a laser or an electron beam to form a modeled object. However, if the height between the base plate and the supply port of the processed material for supplying the metal material to the formed model is out of the appropriate value range, the metal material can be uniformly laminated. Can not. For example, if the metal material is provided from a supply port higher than the appropriate value range for the formed model, in other words, if the height of the model is lower than the design value, the supplied metal. The material becomes droplets, and the modeled object becomes uneven. On the other hand, if the formed model is supplied from a supply port lower than the appropriate value range, in other words, if the height of the model is higher than the design value, the metal material becomes the model. Undissolved residue is generated due to the effect of being pressed too much.

Therefore, it is necessary to measure the height of the formed model and control the height of supplying the metal material within an appropriate value range. There is an optical cutting method as a method of measuring the height of a modeled object. In the light cutting method, a light receiving optical system is arranged so that a line beam is irradiated to an object as illumination light for measurement, the illumination light is obliquely incident on the object, and the light reflected by the object can be received. As a result, the illumination light receives the reflected light reflected on the object. In the optical cutting method, the height distribution of the object is calculated from the light receiving position of the reflected light in the light receiving optical system by the principle of triangulation. Specifically, the reflected light reflected on the object is received by an image sensor or the like. The position of the center of gravity of the reflected light image is calculated from the intensity distribution on the image sensor, and the distance to the object is calculated as the displacement. When ambient light other than the illumination light for measurement is incident on the image sensor, an error occurs in the calculation result of the center of gravity, so that a measurement error occurs in the height measurement result. In Patent Document 1, in order to remove ambient light, an optical filter that transmits only the wavelength of the illumination light for measurement is attached to the light receiving optical system, and the transmission wavelength is changed according to the spread angle of the illumination light. , A method of transmitting light having a wavelength generated by a change in the reflected wavelength due to an increase in the incident angle of light, removing ambient light, and reducing a height measurement error is described.

Japanese Unexamined Patent Publication No. 2012-242134

However, the processing position of the laminated molding apparatus becomes high enough to melt a processing material such as metal. Therefore, very high-intensity thermal radiant light is generated at the processing position of the laminated modeling apparatus. When such high-intensity thermal radiant light is generated, the thermal radiant light becomes high-intensity ambient light when measuring the height of the formed modeled object, so that the reflected light obtained from the image on the image sensor is obtained. The position of the center of gravity of the image becomes unstable, and the measured value also has an error. Further, the high-intensity thermal radiant light generated at the processing position has a wide spectrum and includes light having a wavelength generally used for measurement illumination light. Therefore, in the method described in Patent Document 1, since a wavelength selection filter that transmits only the wavelength of the illumination light for measurement is used, the thermal radiant light generated from the processing position cannot be completely removed. There is a problem that the measurement accuracy during processing of the height of the formed shaped object deteriorates.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain a laminated modeling apparatus capable of suppressing deterioration of measurement accuracy during processing of the height of a formed model. And.

In order to solve the above-mentioned problems and achieve the object, the laminated molding apparatus according to the present invention performs additional processing by laminating molten processed material at the processing position while moving the processing position on the work. It is a laminated molding device that repeats additional processing to form a modeled object, and is used for measurement at a processing optical system that forms an image of processing light that melts the processing material at the processing position and at a measurement position different from the processing position on the workpiece. It is formed on the work based on the measurement illumination that irradiates the illumination light, the light receiving optical system including the light receiving element that receives the reflected light reflected at the measurement position, and the light receiving position of the reflected light on the light receiving element. It is equipped with a calculation unit that calculates the height of the modeled object, and the light receiving optical system transmits light at the imaging position of the reflected light that is reflected at the measurement position and is incident on the light receiving element, and is incident from the processing position. It is characterized by providing a light-shielding mask that blocks light at the position where the light is imaged.

According to the present invention, there is an effect that deterioration of measurement accuracy during processing of the height of the formed shaped object can be suppressed.

The perspective view which shows the structure of the laminated modeling apparatus which concerns on Embodiment 1. The figure which shows the control circuit which concerns on Embodiment 1. The figure which shows the cross section of the XZ plane of the laminated modeling apparatus in line III-III of FIG. The figure which shows the height of the supply port of the metal wire with respect to the modeled object which concerns on Embodiment 1. The figure which shows the XZ cross section of the processing point during processing which concerns on Embodiment 1. Flow chart showing the procedure of wire height control according to the first embodiment The figure which shows the wire height at the time of processing the 2nd layer by the laminated modeling apparatus which concerns on Embodiment 1. The figure which shows the enlarged XZ cross section of the model | shaped object which projected the line illumination which concerns on Embodiment 1. The figure which shows the image of the line beam formed on the light receiving element at the time of irradiating the model | shaped object which concerns on Embodiment 1 with a line beam. The figure which shows the outline of the imaging result of the image sensor which is the light receiving element under processing which concerns on Embodiment 1. The figure which shows the image output from the image sensor which concerns on Embodiment 1. The figure which shows the structural example of the light-shielding mask which concerns on Embodiment 1. Another figure showing a configuration example of the light-shielding mask according to the first embodiment. Another view showing a cross section of the XZ plane of the laminated modeling apparatus in lines III-III of FIG. The figure which shows the XZ cross section of the laminated modeling apparatus which concerns on Embodiment 2. The figure which shows the relationship between the thickness of the light-shielding mask which concerns on Embodiment 2 and the area of a light-shielding part. The figure of the 1st example which shows the XY cross section at the time of performing the processing which changed the forming direction of the modeled object which concerns on Embodiment 3. FIG. 2 is a diagram of a second example showing an XY cross section when processing is performed in which the forming direction of the modeled object according to the third embodiment is changed. FIG. 3 is a diagram of a third example showing an XY cross section when processing is performed in which the forming direction of the modeled object according to the third embodiment is changed.

Hereinafter, the laminated modeling apparatus according to the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.

Embodiment 1.
FIG. 1 is a perspective view showing the configuration of the laminated modeling apparatus 100 according to the first embodiment. Including the following embodiments, the laminated modeling apparatus 100 is a metal laminating apparatus that uses metal as a processing material, but may use other processing materials such as resin. .. Further, the modeled object formed by the laminated modeling apparatus 100 may be referred to as a laminated product. The laminated modeling apparatus 100 of the present embodiment includes a processing laser 1, a processing head 2, a fixture 5, a drive stage 6, a line illumination 8, a calculation unit 9, and a control unit 10.

The processing laser 1 is a light source that emits processing light used for modeling to form a model 4 on a work 3. As the processing laser 1, a fiber laser using a semiconductor laser or a CO ₂ laser is used. For example, the wavelength of the processing light emitted by the processing laser 1 is 1070 nm. Generally, the processing light is focused in a dot shape at the processing position, so the processing position will be referred to as a processing point hereafter. The laminated modeling apparatus 100 forms the modeled object 4 by melting and laminating the processing material 7 at the processing position each time the processing is performed while moving the processing position on the work 3, that is, while scanning.

The work 3 is placed on the drive stage 6 and fixed on the drive stage 6 by the fixture 5. The work 3 serves as a base when the modeled object 4 is formed. Here, the base plate is assumed as the work 3, but any object having a three-dimensional shape may be used. By driving the drive stage 6, the position of the work 3 with respect to the processing head 2 changes, and the processing point on the work 3 is scanned. Scanning a machining point means that the machining point moves along a defined path, that is, in a defined trajectory. The laminated modeling apparatus 100 performs additional processing by laminating the molten processing material 7 at the processing point while moving the processing point which is the processing position on the work 3. In other words, the laminated modeling apparatus 100 performs additional processing by laminating the molten processing material 7 at a processing point that moves on the work 3. More specifically, the laminated modeling apparatus 100 moves a candidate point for a machining position on the work 3 by driving the drive stage 6. At least one of the candidate points on the movement path is a processing point on which the processing material 7 is laminated. At the processing point, the laminated modeling apparatus 100 melts the processing material 7 supplied for performing additional processing with processing light. By repeating the scanning of the processing points, the laminated modeling apparatus 100 laminates the beads generated by solidifying the molten processing material 7, and forms the modeled object 4 on the work 3. As the drive stage 6, a 5-axis stage capable of scanning the XYZ on three axes and rotating in the XY plane and the YZ plane is often used. For example, the X-axis is the horizontal axis, the Y-axis is the vertical axis, and the Z-axis is the height axis. Here, the drive stage 6 is scanned on five axes, but the machining head 2 may be scanned.

The line illumination 8 irradiates a measurement position on the work 3 with a line beam 40, which is a line-shaped illumination light for measurement, in order to measure the height of the formed shaped object 4. The measurement position is different from the machining point. The line illumination 8 is also called a measurement illumination. The line beam 40 reflects at the measurement position. The light receiving optical system is arranged so that the light reflected at the measurement position can be received. Further, the light receiving optical system is arranged so as to have an optical axis in an oblique direction with respect to the optical axis of the line beam 40. Since the peak wavelength of the thermal radiant light generated during processing is infrared, the light source of the line illumination 8 is a green laser having a wavelength of about 550 nm or a blue laser having a wavelength of about 420 nm, which is separated from the peak wavelength of the thermal radiant light. It is desirable to use it. The illumination light used to measure the height of the modeled object 4 does not have to be the line beam 40, and may be a spot beam which is the illumination light condensed in a dot shape. If the spot beam is used, the height of the illuminated point on the work 3 can be measured. On the other hand, if the line beam 40 is used, the height distribution of the illuminated range on the work 3 can be measured. In the present embodiment, it is assumed that the line beam 40 is used to measure the height of the modeled object 4.

The calculation unit 9 calculates the height of the modeled object 4 at the position where the line beam 40 is irradiated, based on the light receiving position of the reflected light of the line beam 40 in the light receiving optical system, according to the principle of triangulation. The height of the modeled object 4 is the position of the upper surface of the modeled object 4 in the Z direction. Further, the control unit 10 controls the processing conditions in the additional processing by using the height calculated by the calculation unit 9. More specifically, the control unit 10 uses the height of the modeled object 4 calculated by the calculation unit 9 to drive the processing laser 1 and the drive stage 6, and the metal to be the processing material 7. Optimize machining conditions such as drive conditions for the wire supply unit that supplies the wire. The drive condition of the wire supply unit includes the height at which the metal wire is supplied. The line illumination 8, the light receiving optical system, and the calculation unit 9 constitute a height measuring device.

The arithmetic unit 9 and the control unit 10 according to the embodiment are realized by a processing circuit which is an electronic circuit that performs each processing.

The processing circuit may be dedicated hardware or a control circuit including a memory and a CPU (Central Processing Unit) that executes a program stored in the memory. Here, the memory corresponds to, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), or a flash memory, a magnetic disk, an optical disk, or the like. When the processing circuit is a control circuit including a CPU, the control circuit is, for example, the control circuit 200 having the configuration shown in FIG.

As shown in FIG. 2, the control circuit 200 includes a processor 200a which is a CPU and a memory 200b. When it is realized by the control circuit 200 shown in FIG. 2, it is realized by the processor 200a reading and executing the program corresponding to each process stored in the memory 200b. The memory 200b is also used as a temporary memory in each process performed by the processor 200a.

FIG. 3 is a diagram showing a cross section of the XZ plane of the laminated modeling apparatus 100 in lines III-III of FIG. The processing head 2 includes a floodlight lens 11, a beam splitter 12, an objective lens 13, a condenser lens 14, a light-shielding mask 15, a second imaging optical system 16, and a light receiving unit 17. The processing head 2 is a processing optical system 20 that forms an image of processing light emitted from the processing laser 1 at a processing position on the work 3, and light receiving optics that measures the height of the modeled object 4 formed on the work 3. A system 30 is provided. The first imaging optical system including the objective lens 13 and the condenser lens 14, the light-shielding mask 15, the second imaging optical system 16, and the light receiving unit 17 constitute the light receiving optical system 30. The light receiving optical system 30 is also called a measuring optical system. The processing light emitted from the processing laser 1 passes through the floodlight lens 11, is reflected in the direction of the work 3 by the beam splitter 12, and is focused on the processing point on the work 3 by using the objective lens 13. The floodlight lens 11, the beam splitter 12, and the objective lens 13 constitute a processing optical system 20 provided in the processing head 2. For example, the focal length of the floodlight lens 11 is 200 mm. For example, the focal length of the objective lens 13 is 460 mm. The surface of the beam splitter 12 is coated so as to increase the reflectance of the wavelength of the processing light emitted from the processing laser 1 and to transmit light having a wavelength shorter than the wavelength of the processing light. The laminated modeling apparatus 100 supplies the metal wire or metal powder as the processing material 7 to the processing point while scanning the work 3 in the −X direction by driving the drive stage 6. As a result, as the processing point is scanned, the processing material 7 is melted by the processing light at the processing point and then solidified, and the bead is formed so as to extend in the + X direction. The formed bead becomes a part of the model 4.

Each time the machining point is scanned, a new bead is laminated on a part of the work 3 or the modeled object 4 which is the base, so that a part of the new modeled object 4 is formed. By repeating this operation, the processing materials 7 are laminated to form the final product, the modeled object 4. In the present embodiment, the description will proceed assuming that the metal wire is used as the processing material 7. The line illumination 8 for height measurement is attached to the side surface of the processing head 2 and irradiates the line beam 40 toward the measurement position on the work 3 or the formed model 4. In the present embodiment, the measurement position is located behind the machining point in the scanning direction of the machining point. When the work 3 is scanned in the −X direction, the machining point is scanned in the + X direction on the work 3, so that the back of the machining point is in the −X direction and the bead extends in the + X direction. It is formed. The measurement position is not limited to the rear of the machining point as long as it is different from the machining point, and may be, for example, the front of the machining point. The measurement position is determined in consideration of the supply direction of the processing material 7. For example, if the measurement position is on the side opposite to the supply direction of the processing material 7 with respect to the processing point, it becomes easy to illuminate the measurement position without being blocked by the processing material 7. Further, the measurement position may be moved in accordance with the movement of the processing point. Here, the beads will be described as being formed so as to extend linearly, including the following embodiments, but other bead forming methods such as connecting the beads formed in a dot shape to form one bead. But it's okay.

The line beam 40 forms a beam that is perpendicular to the direction in which the bead is formed, that is, the direction in which the drive stage 6 moves, and extends in a direction parallel to the upper surface of the drive stage 6, for example, the Y direction. It is formed using a right-angled cylindrical lens or the like. Here, the spread of the beam means a portion of the base of the isosceles triangle formed by the line beam 40. The line beam 40 irradiates the formed model 4 in a line shape. The line beam 40 irradiated to the measurement position is reflected at the measurement position, enters the objective lens 13, passes through the beam splitter 12, and is focused by the condenser lens 14 at the first imaging position. The objective lens 13 and the condenser lens 14 are collectively referred to as a first imaging optical system.

A light-shielding mask 15 is installed at the first image-forming position, which is the image-forming surface of the condenser lens 14. The light-shielding mask 15 is based on a transparent material such as glass, and a light-shielding material that blocks light is formed by vapor deposition or the like at an image formation position of light from a processing point. The light-shielding mask 15 can be manufactured, for example, by depositing a light-shielding material such as chromium oxide on a transparent material such as glass. The light-shielding mask 15 may have other configurations as long as it has a function of blocking the image formation position of the light from the processing point and not blocking the image formation position of the reflected light from the measurement position. The light transmitted through the light-shielding mask 15 is imaged on the light receiving unit 17 using the second imaging optical system 16. The second imaging optical system 16 is configured in the same manner as the first imaging optical system using, for example, two lenses, but may be one lens or three or more lenses, and the light receiving unit 17 may be used. It suffices if it has a function capable of forming an image. An area camera or the like equipped with a light receiving element such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor is used as the light receiving unit 17, but the light receiving unit 17 may be configured to include a light receiving element in which pixels are arranged two-dimensionally. It is desirable to insert a bandpass filter that transmits only the irradiation wavelength of the line beam 40 in the optical system from the beam splitter 12 to the light receiving unit 17. By providing the bandpass filter, it is possible to remove light having an unnecessary wavelength among processing light, thermal radiation light, ambient light and the like. As described above, the light receiving optical system 30 includes a light shielding mask 15 that shields the light emitted at the processing point and incident on the light receiving element, and does not shield the reflected light reflected at the measurement position and incident on the light receiving element. In other words, the light receiving optical system 30 transmits light at the imaging position of the reflected light reflected at the measurement position and incident on the light receiving element, and blocks the light at the imaging position of the light incident from the processing position. A mask 15 is provided.

The laminated modeling apparatus 100 supplies a metal wire as a processing material 7 to a processing point and irradiates the processing point with processing light to laminate a new layer on the formed model 4 to create a new model. Perform the additional processing set to 4. FIG. 4 is a diagram showing the height of the metal wire supply port with respect to the modeled object 4 according to the first embodiment. Here, the height of the metal wire supply port indicates the height of the metal wire supply port with respect to the upper surface of the work 3. Hereinafter, the height of the metal wire supply port may be simply referred to as the height of the supply port. If the amount of metal wire emitted from the supply port is set to a known value, the height of the tip of the metal wire can also be calculated from the height of the supply port. The amount of the metal wire emitted from the supply port represents the length from the supply port to the tip of the metal wire. By controlling the height of the supply port, the height of the tip of the metal wire can be controlled. Here, it is assumed that the amount of the metal wire emitted from the supply port is controlled to be constant, and the height of the supply port and the height of the tip of the metal wire have a one-to-one correspondence. Further, the range of the appropriate height of the supply port depends on the height of the modeled object 4 that has already been modeled. As shown in FIG. 4, if the metal wire cannot be supplied to the formed model 4 at an appropriate height, a defect will occur in the processing result. For example, as shown in FIG. 4A, an appropriate height range of the supply port according to the formed model 4 is set to ha ± α. In FIG. 4A, the height of the supply port is the center of the range of ha ± α. That is, in FIG. 4A, the height of the supply port is ha. In FIG. 4A, ha + α is shown as the upper limit value 51. In FIG. 4A, ha-α is shown as the lower limit value 50. In FIG. 4A, the height of the supply port is ha, which is within the range of ha ± α, so that no problem occurs in the processing result. However, in FIG. 4B, the height hb of the supply port is hb> ha + α, which is outside the range of ha ± α. In this case, since the position where the metal wire melts is far from the modeled object 4, the metal wire melted by being irradiated with the processing light does not sufficiently adhere to the formed modeled object 4, and droplets are generated after processing. Unevenness is generated in the modeled object 4. Further, in FIG. 4C, the height hc of the supply port is hc <ha−α, which is outside the range of ha ± α. In this case, the metal wire is pressed too much in the direction of the formed object 4, and even if the processing light is irradiated, all the metal wire is not completely melted, and the unmelted metal wire is generated. As a result, the metal wire left undissolved in the modeled object 4 after processing is included. As described above, it is indispensable for high-precision machining to keep the height of the supply port corresponding to the formed model 4 at an appropriate value during machining. In the case of the first layer in which the modeled object 4 is started to be processed with respect to the work 3, if the height of the work 3 is flat, the height of the supply port may be kept constant for processing.

However, after the second layer, it is necessary to process the modeled object that has been formed by the previous time (previous layer). Here, it is conceivable that the height of the modeled object 4 that has been formed up to the previous time is not the height as designed, or the height of the modeled object 4 is not constant depending on the position. In this case, even if the supply port is raised by the height of one layer by design from the height of the supply port at the time of the previous stacking, the actual height of the modeled object up to the time of the previous stacking is actually reached. However, in the part where is different from the design value, the height of the supply port may not be within the appropriate range of the supply port corresponding to the part to be laminated this time. It is also possible that the height of the model 4 is not constant depending on the position. If the second layer is within the appropriate height range (ha ± α), in other words, within the permissible error range, it is processed multiple times, and when the nth layer (n ≧ 2) is processed, it is laminated. Since the error is added n times, it may not fall within the permissible error range (ha ± α). Here, it is necessary to measure the height of the modeled object 4 after processing and perform control by using this height information at the next processing.

Here, a method of maintaining the metal wire at an appropriate height with respect to the formed model 4 by using the measured height of the formed model 4 will be described. After processing the modeled object 4, it is also possible to scan the same path again for measurement separately from the processing and measure the height of the formed modeled object 4. However, in this case, it takes time because it is necessary to scan the processing path twice for the additional processing of one layer. Here, by measuring the height of the modeled object 4 formed during processing, the heights of the additional processed object 4 and the formed object 4 can be measured while scanning the processing path for one layer of additional processing at one time. Both measurements can be made. FIG. 5 is a diagram showing an XZ cross section of a processing point during processing according to the first embodiment. The region where the processing light is applied to the processing point during the additional processing and the metal wire is melted on the work 3 is called a melt pool. For example, by scanning the drive stage 6 on which the work 3 is placed in the −X direction, a linear model 4 can be added in the X direction. The temperature near the melt pool at the processing point is high, but as the drive stage 6 is moved, the melt pool is naturally cooled and solidifies into a constant shape as a metal bead. The beads are laminated to form the model 4.

Here, the end of the melt pool is set to the center of the processing point, that is, a position separated from the optical axis of the processing laser beam by a distance W. In the melt pool, the processed material is melted, and it is difficult to accurately measure the height of the formed model. Therefore, it is desirable that the irradiation position of the line beam 40 for measuring the height is a position separated from the center of the processing point by a distance W or more. For example, it is desirable that the irradiation position of the line beam 40 for measuring the height is a position separated from the center of the processing point by a distance L. That is, it is desirable that the measurement position where the height is measured is a position outside the range in which the processing material 7 is melted during processing. When the irradiation position of the line beam 40 is far from the processing point, the beads are sufficiently solidified and it is easy to measure. However, when the irradiation angle of the line beam 40 is constant, the installation position must be separated from the processing head 2, and the device Becomes larger. Further, when the installation position of the line beam 40 is set near the processing head 2, the irradiation angle becomes vertical, so that the displacement of the irradiation position of the line beam 40 with respect to the height change is small, and the height resolution is lowered. Further, when the imaging system is installed coaxially with the processing head 2, the field of view needs to be increased, so that the resolution is lowered. If the imaging system is provided separately from the processing head 2, the device becomes large. As described above, the measurement position is determined in consideration of various matters. In particular, the measurement position needs to be determined in consideration of the height range in which measurement is required. The height range that needs to be measured is determined according to the specifications of the laminated modeling apparatus 100.

The light receiving position on the light receiving element of the reflected light reflected at the measurement position of the illumination light for height measurement such as the line beam 40 changes depending on the height of the measurement position. Here, with respect to the height range in which measurement is required, the range on the light receiving element where the reflected light reflected at the measurement position is received and the image of the range in which the processing material 7 is melted during processing are displayed. It is necessary to set the measurement position so as not to overlap the range on the light receiving element that is imaged when the light blocking mask 15 is not provided. With this configuration, it is possible to optically separate the reflected light from the measurement position and the disturbance light generated at the processing position. The light-shielding mask 15 shields the thermal radiant light radiated from the processing point so that it is not received on the light receiving element, and the reflected light reflected at the measurement position is transmitted without being shielded. For example, the light-shielding mask 15 is configured to block only the range of the optical path where the thermal radiant light emitted from the processing point is incident on the light receiving element. Further, for example, the light-shielding mask 15 is configured to block light from the height range in which measurement is required, excluding the range of the optical path in which the reflected light reflected at the measurement position is incident on the light receiving element.

FIG. 6 is a flowchart showing the procedure of wire height control according to the first embodiment. Here, the wire height is the height of the tip of the processing material 7 irradiated with the processing light with respect to the upper surface of the work 3. The wire height is the height of the tip of the processing material 7 in a state where the processing material 7 is not melted. First, the laminated modeling apparatus 100 starts the additional processing of the first layer (step S1). Further, the laminated modeling apparatus 100 starts measuring the height of the modeled object 4 after processing (step S2), and saves the height of the modeled object 4 with respect to the measurement position to complete the additional processing of the first layer (step S2). Step S3). Here, the height interval of the modeled object 4 that can be measured is determined by the frame rate of the image sensor used as the light receiving element in the light receiving unit 17 and the scanning speed of the processing axis (scanning speed of the processing point). For example, assuming that the frame rate is F [fps] and the moving speed of the drive stage 6 is v [mm / s], the measurement interval Λ [mm] in the scanning direction of the processing point at the height of the modeled object 4 is Λ = v / F. It becomes. Further, when the moving range of the drive stage 6 is P × Q [mm], the height measurement result of the maximum P / Λ × Q / Λ can be measured at the time of processing the first layer. After that, the laminated modeling apparatus 100 changes the height of the wire (step S4) and starts the additional processing of the nth layer (step S5). The laminated modeling apparatus 100 starts measuring the height of the modeled object 4 after processing the nth layer (step S6), and by preserving the height of the modeled object 4 with respect to the measurement position, the nth layer is additionally processed. Finish (step S7). When the laminating modeling apparatus 100 completes the addition processing of all the layers (steps S8, Yes), the processing ends. If the laminated modeling apparatus 100 has not completed the addition processing of all the layers (steps S8 and No), the process returns to step S4.

FIG. 7 is a diagram showing the wire height when the laminated modeling apparatus 100 according to the first embodiment processes the second layer. When processing the second layer, for example, as shown in FIG. 7, as a result of measuring the height of the modeled object 4 formed by the first layer, the area I can be modeled at the height T1 as designed, and the area II can be formed. Is T2 higher than the design and region III is T3 lower than the design. Here, when the wire height is adjusted using the average value Tave = T1 of the height measurement results of all the regions, the wires are separated by Tave in the + Z direction and the processing of the second layer is started. Here, for adjusting the wire height at the time of machining the second layer, the design load capacity for one layer, the maximum value of the measured height measurement result, the median value, or the like may be used. When the second layer is laminated at each processing position, the measured heights T1 to T3 in each region of the first layer and the target lamination height (2 × T1) in the second layer are adjusted according to the difference. , The control unit 10 changes the machining conditions.

If the measured wire height T1 = the target molding height in the first layer as in region I, the processing is performed under standard processing conditions (processing laser output, wire supply amount, scanning speed of drive stage 6, etc.). I do. On the other hand, when the measured wire height T2> the target modeling height in the first layer as in region II, the processing conditions are set so that the height of the modeled object 4 in all regions becomes uniform after the second layer. Change to reduce the stacking amount of the second layer. For example, the processing laser output is reduced, or the amount of wire supplied is reduced. Further, when the measured wire height T3 <target modeling height in the first layer, the processing conditions are changed so that the height of the modeled object 4 in all areas becomes uniform after the second layer, and the second layer is used. Increase the stacking amount. For example, the processing laser output is increased or the amount of wire supplied is increased. Then, the height of the modeled object 4 after laminating is also measured at the time of laminating the second layer. When the measured height of the second layer is a relative height based on the height of the first layer, the total stacking amount can be calculated by adding it to the measurement result of the first layer. Further, when the height of the processing head 2 is adjusted each time each layer is laminated, the height of the modeled object 4 is required in consideration of the adjusted height of the processing head 2. In this way, using the result of the bead height measured during the n-1st lamination, the wire height is increased by a certain amount during the nth lamination, and the machining conditions are applied to the height change at each machining position. By controlling the above, control is performed so that the stacking amount at all the processing positions becomes uniform after the processing of each layer is completed. By doing so, the wire height with respect to the modeled object 4 can always be maintained at ha ± α, so that the machining can be continued without causing a machining defect.

Next, a height measurement operation using the optical cutting method for measuring the bead height after processing will be described. FIG. 8 is a diagram showing an enlarged XZ cross section of the modeled object 4 on which the line illumination 8 according to the first embodiment is projected. In FIG. 8, assuming that the height of the modeled object 4 with respect to the work 3 is ΔZ and the irradiation angle of the line beam 40 is θ, the difference ΔX between the irradiation positions of the line beam 40 on the work 3 and the modeled object 4 is ΔX. It is represented by = ΔZ / tan θ. FIG. 9 is a diagram showing an image of the line beam 40 formed on the light receiving element when the model 4 according to the first embodiment is irradiated with the line beam 40. Since the line beam 40 irradiated by the line illumination 8 is sufficiently stronger than the ambient light, only the line beam 40 appears in the image acquired by the light receiving element. Due to the difference in height between the model 4 and the work 3, the irradiation position of the line beam 40 is projected with a deviation of ΔX'. Here, when the magnification M1 of the first imaging optical system and the magnification M2 of the second imaging optical system 16 are used, ΔX ′ = M1 × M2 × ΔX. Assuming that the size of one pixel of the image sensor is W, the height displacement amount ΔZ ′ per pixel is expressed as ΔZ ′ = W × tan θ / (M1 × M2). For example, if W = 5.5 μm, M1 = 1/2, M2 = 1, θ = 72 deg, then ΔZ ′ = 30 μm. In this way, the height from the sensor to the object can be calculated from the projection position of the line beam 40 of the image sensor image by the principle of triangulation.

Further, the height of the modeled object 4 can be calculated from the difference in the irradiation position of the line beam 40 between the upper surface of the work 3 and the upper surface of the modeled object 4. Even if the height of the model 4 becomes higher than the upper surface of the work 3 and the reflected light of the line beam 40 from the upper surface of the work 3 cannot be received, the line beam 40 reflected from the upper surface of the model 4 in the field of view. The distance from the sensor can be calculated using the irradiation position of. The irradiation position of the line beam 40 is generally calculated from the position of the center of gravity in the X direction of the projection pattern of the line beam 40. The output in the X direction is calculated for each pixel in the Y direction, and the position of the center of gravity is calculated from the cross-sectional intensity distribution of the line beam 40. Here, the method of calculating the irradiation position of the line beam 40 is not limited to the position of the center of gravity, and the peak position of the amount of light is appropriately selected. The irradiation width of the line beam 40 needs to be large enough for the calculation of the irradiation position. For example, in the case of calculating the center of gravity, if it is too narrow, the center of gravity cannot be calculated, and if it is too thick, an error is likely to occur due to the influence of the change in the intensity pattern of the beam. Therefore, about 5 to 10 pixels is desirable. Further, the line length of the line beam 40 (irradiation width of the line beam 40) may be sufficiently longer than the width of the modeled object 4. By calculating the position of the center of gravity of the brightness in the X direction for each pixel in the Y direction of the image and converting the result into the height in this way, the cross-sectional distribution of the height of the model 4 in the width direction of the model 4 Can be measured. When a spot beam is used as the illumination light used to measure the height of the modeled object 4, the cross-sectional distribution of the height of the modeled object 4 cannot be measured, but the spot size is appropriately selected. By doing so, measurement with less error becomes possible.

Up to this point, the method of calculating the height of the modeled object 4 from the line beam 40 in the unprocessed state has been described, but when measuring during processing, the processing point becomes a high-intensity light emitting point, and the processing point becomes a processing point. A measurement error occurs due to the stray light in the imaging system generated by the heat radiant light emitted from the image. FIG. 10 is a diagram showing an outline of an imaging result of an image sensor which is a light receiving element during processing according to the first embodiment. When the line beam 40 is imaged on the image sensor during processing without the light-shielding mask 15, the thermal radiant light emitted from the processing point is also imaged on the image sensor. As described above, since the irradiation position of the line beam 40 is separated from the melt pool, it is possible to separate the heat radiant light emitted from the processing point and the reflected light of the line beam 40. However, in an imaging system that does not use the light-shielding mask 15, it is conceivable that the thermal radiant light generated from the processing point is reflected inside the housing of the imaging system and becomes stray light. There is no problem if the brightness of the thermal radiant light is sufficiently smaller than the brightness of the line beam 40 which is the signal light, but the brightness of the thermal radiant light at the processing point generated by the laser processing is very large. Therefore, it is considered that the stray light generated in the housing cannot be ignored. In addition, the thermal radiant light imaged on the image sensor is also reflected multiple times in the transparent resin for protecting the surface of the image sensor, or is reflected by the metal part of the light receiving portion 17 of the image sensor to generate stray light. It is possible to make it.

In this way, when the stray light in the imaging system generated by the thermal radiation light from the high-brightness processing point is incident on the light receiving element together with the line beam 40 which is the signal light, it becomes noise and the calculation result of the position of the center of gravity of the brightness becomes noise. There is an error in. Here, in order to suppress the generation of stray light as much as possible, the light-shielding mask 15 is used to block the heat radiant light in the imaging system so that the heat radiant light does not reach the light receiving element. As shown in FIG. 3, the shading mask 15 is installed at the focal position of the first imaging optical system. At the focal position of the first imaging optical system, an image on the work 3 side is imaged at a magnification of M1. Therefore, assuming that the size of the melt pool is φ2W, the size of the light-shielding portion may be set to φ2W × M1 or more in order to block the heat radiant light generated from the processing point. However, if the size of the light-shielding portion is too large, the line beam 40 is also shielded from light, so it is necessary to make it φ2 (L−ΔL) × M1 or less. FIG. 11 is a diagram showing an image output from the image sensor according to the first embodiment. As shown in FIG. 11, in the image output from the image sensor, the light from the processing point is blocked, and the stray light incident along with the reflected light of the line beam 40 can be removed. The installation position of the light-shielding mask 15 is the focal position of the first imaging optical system, but it is not necessary to exactly match the focal position, and if the light-shielding mask 15 deviates from the light-shielding position, the light-shielding portion of the light-shielding portion The same effect can be obtained by designing the size to be large. FIG. 12 is a diagram showing a configuration example of the light-shielding mask 15 according to the first embodiment. FIG. 13 is another diagram showing a configuration example of the light-shielding mask 15 according to the first embodiment. As the configuration of the light-shielding mask 15, for example, when a circular housing is used, a configuration in which only the processed portion is shielded as shown in FIG. 12 is shown, but a configuration as shown in FIG. 13 in which only the line beam 40 is transmitted is shown. However, it suffices if the imaging position of the processing point is shielded from light.

Here, in the height measuring device of the present invention, since the light-shielding mask 15 that transmits only the line beam 40 is used, the condenser lens 14 and the second imaging optical system 16 that are not used for both processing and height measurement are used together. Is preferably an optical system capable of forming an image of only the line beam 40 on the light receiving unit 17. FIG. 14 is another view showing a cross section of the XZ plane of the laminated modeling apparatus 100 in lines III-III of FIG. For example, as shown in FIG. 14, the central axis of the objective lens 13 and the central axis of the condenser lens 14 or the central axis of the second imaging optical system 16 in a direction perpendicular to the central axis of the objective lens 13. And are off-axis. Here, the objective lens 13 is a lens that collects the processing light at the processing position. Further, the condenser lens 14 and the second imaging optical system 16 form a third imaging optical image of the reflected light transmitted through the objective lens 13 on the light receiving unit 17 among the reflected light of the illumination light for measurement. Construct a system.

Therefore, in the configuration shown in FIG. 14, the position of the central axis of the third imaging optical system that forms an image of the reflected light transmitted through the objective lens 13 on the light receiving unit 17 is the objective lens 13 that collects the processed light at the processed position. It is different from the position of the central axis of. With such a configuration, the reflected light of the line beam 40, which is the illumination light for measurement, can be imaged on the light receiving element without being affected by the aberration of the lens as much as possible, and the height measurement accuracy can be improved. .. Instead of the configuration in which the position of the central axis is shifted as described above, the central axis of the third imaging optical system that forms an image of the reflected light transmitted through the objective lens 13 on the light receiving unit 17 is the processed light at the processed position. The same effect can be obtained by adopting a configuration that is tilted with respect to the central axis of the objective lens 13 that collects light. Further, the shape of the lens surface of the condenser lens 14 may be changed. Further, the field of view of the light receiving unit 17 may be wider than the range in which the line beam 40 moves within the height measurement range, and a second imaging optical system 16 that expands only the moving range of the line beam 40 is used. The resolution of the line beam 40 can be increased, and the height measurement accuracy can be improved.

Here, a height measuring method in the case where the work 3 is scanned in the −X direction and formed so that the bead extends in the direction in which the wire is supplied, that is, in the + X direction has been described. In this case, since the height of the modeled object 4 immediately after processing is measured, this result may be used at the next processing. On the other hand, the work 3 may be scanned in the + X direction opposite to the direction in which the wire is installed so that the bead extends in the direction opposite to the direction in which the wire is installed, that is, in the −X direction. In this case, since the height of the modeled object 4 machined last time is measured immediately before the current machining, the machining conditions may be controlled immediately after the measurement. However, since the average stacking height of the laminate at the time of the previous machining cannot be known at the time of wire height adjustment before starting this scanning, the wire height is adjusted using the design value, etc., and the design value is used. The difference in the stacking amount from the above is measured, and this result is reflected in the control during machining.

In this way, when the height measuring system of the optical cutting method using the line illumination 8 is incorporated in the laminated molding apparatus 100 and the height of the modeled object 4 is measured during processing, once in the imaging system for height measurement. , An image of a processing point is imaged, a light-shielding mask 15 having a light-shielding portion that blocks the image-forming position is installed on the image-forming surface, and the light-shielding mask 15 is provided by using the second imaging optical system 16. By forming an image of only the transmitted line illumination 8, stray light generated in the housing of the heat radiant light generated from the high-brightness processing point or in the light receiving unit 17 is suppressed, and the height of the modeled object 4 can be adjusted with high accuracy. It becomes possible to measure. Therefore, the laminated modeling device 100 can suppress deterioration in the accuracy of measuring the height of the formed model 4.

Embodiment 2.
The laminated modeling apparatus according to the second embodiment has the same configuration as the laminated modeling apparatus according to the first embodiment, but the configuration of the height measurement optical system is different. The laminated modeling apparatus according to the second embodiment of the present invention has a configuration in which a light-shielding plate in the height measurement optical system is provided not at the focal position of the first imaging optical system but immediately before the image sensor which is a light receiving element. is there. Therefore, there is an advantage that the second imaging optical system 16 can be omitted and the entire device can be miniaturized.

FIG. 15 is a diagram showing an XZ cross section of the laminated modeling apparatus according to the second embodiment. The configuration of the processing laser 1, the processing optical system 20, and the line illumination 8 is the same as that of the first embodiment. In the present embodiment, the reflected light from the model 4 transmitted through the beam splitter 12 is directly imaged on the light receiving element of the light receiving unit 17 by the condenser lens 14. Further, by installing a light-shielding mask 15 immediately before the light-receiving element, that is, between the light-receiving element and the first imaging optical system, the thermal radiant light from the processing point is blocked, and only the reflected light of the line beam 40 is blocked. Is imaged on the image sensor. The light-shielding mask 15 is attached on the image sensor by a method such as adhesion. The size of the light-shielding portion on the light-shielding mask 15 needs to be set according to the distance from the pixels of the image sensor to be installed. Assuming that the region of the melt pool to be shielded from light is φM, the size on the image sensor imaged by the first imaging optical system is φM'= φM × M1. FIG. 16 is a diagram showing the relationship between the thickness of the light-shielding mask 15 and the region of the light-shielding portion according to the second embodiment. As shown in FIG. 16, assuming that the incident angle R of the light beam of the image sensor and the distance D from the image sensor pixel surface of the light-shielding portion, the size of the region φS of the light-shielding portion is φS = φM'+ 2 × Dtan (R). Just do it. However, as the thickness of the light-shielding mask 15, that is, the distance D increases, it is necessary to increase the area φS of the light-shielding portion by this amount, and there is a possibility that the reflected light rays of the line beam 40 imaged on the image sensor will also be blocked. is there. Therefore, it is desirable that the thickness of the light-shielding mask 15 is as thin as possible.

As described above, in the laminated modeling apparatus of the second embodiment, even if one imaging optical system of the height measuring unit is used, the processing point is shielded from light, and the modeled object 4 has high height measurement accuracy even during processing. Since it is possible to measure the height of the device, there is an advantage that the entire device can be miniaturized.

Embodiment 3.
The laminated modeling apparatus of the third embodiment has the same configuration as that of the first embodiment or the second embodiment, but the shape of the line beam 40 used for height measurement is different. In the laminated modeling apparatus according to the third embodiment of the present invention, the irradiation shape of the line beam 40 is not a straight line but a circular shape centered on a processing point. By making the irradiation shape of the line beam 40 circular in this way, even if the machining shape is not a straight line and the scanning direction of the machining point changes during machining, the direction crossing the modeled object 4 at right angles, that is, Since the line illumination 8 can be irradiated in the width direction of the modeled object 4, the rotation mechanism of the drive stage 6 can be eliminated, and the device can be miniaturized. For example, if the drive stage 6 is rotated in the XY plane, the measurement position can be set to be in front of or behind the machining point even when scanning in an oblique direction with respect to the X-axis and the Y-axis. However, by making the irradiation shape of the line beam 40 circular, at least a part of the measurement position can be made to be in front of or behind the machining point without rotating the drive stage 6.

FIG. 17 is a diagram of a first example showing an XY cross section in the case of performing processing in which the forming direction of the modeled object 4 according to the third embodiment is changed. The drive stage 6 shown in FIG. 17 is a rotating stage that rotates in the XY plane. In addition, in FIG. 17 and later, the range surrounded by the dotted line indicates the range in which the laminated modeling apparatus 100 is scheduled to form the modeled object 4. As shown in FIG. 17, when processing is performed by changing the forming direction of the modeled object 4 using the drive stage 6, the work 3 is rotated by β degrees using the rotation stage on the XY plane on the drive stage 6 to perform modeling. Since it can be done, the processing direction is always constant. In this case, even if the linear line beam 40 is used, the line beam 40 can always be irradiated perpendicular to the processing direction of the modeled object 4. FIG. 18 is a diagram of a second example showing an XY cross section in the case of performing processing in which the forming direction of the modeled object 4 according to the third embodiment is changed. The drive stage 6 shown in FIG. 18 is not a rotating stage and does not rotate in the XY plane. As shown in FIG. 18, when processing is performed by changing the forming direction of the modeled object 4 when there is no rotating stage, the operating speed in the X-axis direction and the operating speed in the Y-axis direction are controlled to an appropriate ratio. The processing direction can be changed, but it is necessary to process in an oblique direction with respect to the XY plane. However, if the linear line beam 40 is used, it becomes impossible to measure the cross section perpendicular to the direction in which the modeled objects 4 are stacked so as to extend when the processed objects 4 are processed in the oblique direction. FIG. 19 is a diagram of a third example showing an XY cross section in the case of performing processing in which the forming direction of the modeled object 4 according to the third embodiment is changed. The drive stage 6 shown in FIG. 19 is not a rotating stage and does not rotate in the XY plane. In FIG. 19, a circular line beam 40 is used. In this case, even if the modeled object 4 is processed in an oblique direction, the line beam 40 is irradiated in a circular shape centered on the processing point, so that the modeled object is always at a constant distance from the processing point regardless of the processing direction. The height of 4 can be measured. When the wire is loaded from the + X direction, it is generally processed in the range of 180 degrees in the + Y direction to the −X direction to the −Y direction. Therefore, although the circular line beam 40 has been described here, it does not have to be strictly circular, it may have an elliptical shape, and there is no problem even if it is partially interrupted such as a semicircle. The line beam 40 has already been formed by using the line beam 40 regardless of the direction in which the processing point is scanned as long as the angle of the line range of the line beam that can be taken during the additional processing is 90 degrees or more. The height of the model 4 can be measured. For example, in the case of an arcuate line beam, the central angle may be 90 degrees or more. If a 90-degree arcuate line beam from the -X direction to the + Y direction is used, and if the bead is formed so as to extend in the + X direction and the -Y direction, the measurement is performed immediately after processing. When the bead is formed so as to extend in the −X direction and the + Y direction, the measurement is performed immediately before machining. Further, in the case of a curved line beam, the angle of the range of the line in the tangential direction may be 90 degrees or more. Further, as long as the processing directions are only two directions perpendicular to each other, a square shape such as a square may be used.

The configuration shown in the above-described embodiment shows an example of the content of the present invention, can be combined with another known technique, and is one of the configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

1 Machining laser, 2 Machining head, 3 Work, 4 Modeled object, 5 Fixture, 6 Drive stage, 7 Machining material, 8 Line optics, 9 Computational unit, 10 Control unit, 11 Floodlight lens, 12 Beam splitter, 13 Objective lens, 14 condensing lens, 15 shading mask, 16 second imaging optical system, 17 light receiving part, 20 processing optical system, 30 light receiving optical system, 40 line beam, 50 lower limit value, 51 upper limit value, 100 laminated molding Equipment, 200 control circuit, 200a processor, 200b memory.

Claims (9)

It is a laminated molding device that performs additional processing by laminating melted processing materials at the processing position while moving the processing position on the work, and repeats the additional processing to form a modeled object.
A processing optical system that forms an image of processing light that melts the processing material at the processing position,
A measurement illumination that irradiates a measurement position different from the processing position on the work with an illumination light for measurement,
A light receiving optical system including a light receiving element that receives the reflected light reflected by the illumination light at the measurement position, and a light receiving optical system.
A calculation unit that calculates the height of a modeled object formed on the work based on the light receiving position of the reflected light on the light receiving element.
With
The light receiving optical system is
It is characterized by being provided with a light-shielding mask that transmits light at the imaging position of the reflected light reflected at the measurement position and incident on the light receiving element, and blocks the light at the imaging position of the light incident from the processing position. Laminated molding equipment. The light receiving optical system is
A first imaging optical system that forms an image of the reflected light reflected at the measurement position at the first imaging position,
A second imaging optical system that forms an image of light formed at the first imaging position on the light receiving element, and
With
The laminated modeling apparatus according to claim 1, wherein the light-shielding mask is installed at the first imaging position. The light receiving optical system is
An imaging optical system that forms an image of the reflected light reflected at the measurement position on the light receiving element is provided.
The laminated modeling apparatus according to claim 1, wherein the light-shielding mask is installed between the light receiving element and the imaging optical system. The processing optical system includes an objective lens that collects the processing light at the processing position.
The light receiving optical system includes a third imaging optical system that forms an image of the reflected light transmitted through the objective lens on the light receiving element.
The position of the central axis of the third imaging optical system is different from the position of the central axis of the objective lens.
The laminated molding apparatus according to any one of claims 1 to 3, wherein the central axis of the third imaging optical system is tilted with respect to the central axis of the objective lens. The range on the light receiving element where the reflected light reflected at the measurement position is received with respect to the range of the height at which the processing material is attached to the modeled object, and the processing material when the additional processing is performed. Claims 1 to 4, wherein the measurement position is set so that the image of the range in which the light is melted does not overlap with the range on the light receiving element that is imaged in the absence of the light-shielding mask. The laminated molding apparatus according to any one. The light-shielding mask according to claim 5, wherein the light-shielding mask shields the reflected light reflected at the measurement position from the height range except for the range of the optical path where the reflected light is incident on the light-receiving element. Laminated molding equipment. The laminated molding apparatus according to any one of claims 1 to 6, wherein the illumination light for measurement is a line beam irradiated in a line shape. The laminated molding apparatus according to claim 7, wherein the angle of the line range of the line beam that can be taken during the additional processing is 90 degrees or more. The measurement position moves corresponding to the processing position,
The laminate according to any one of claims 1 to 8, further comprising a control unit that controls the processing conditions of the additional processing at the measurement position based on the height of the modeled object at the measurement position. Modeling equipment.

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